The present invention is related to a pipe plug for sealing underground electric pipings, and more particularly to the one which can be conveniently operated to seal the orifice of a pipe with a single hand.
There is illustrated in FIG.1 a pipe plug according to the prior art, which is generally comprised of a fastening element (1A), a rubber band (2A), a pressure plate (3A) and a lifting eye (4A). The lifting eye (4A) is screwed up with the fastening element (1A) to force the pressure plate (3A) to squeeze the rubber band (2A) for that the pipe plug can be firmly retained in the orifice of a pipe (5). In this structure, the pressure plate (3A) comprises three projecting portions (31A) for the positioning of the pipe plug on the orifice of a pipe. During installation to seal the orifice of a pipe, the pipe plug must be well positioned on the orifice of such a pipe with both hands. While screwing up the lifting eye (4A) with the fastening element (1A) to force the pressure plate (3A) to squeeze the rubber band (2A) to expand, one must firmly press on the pressure plate (3A) with one hand and turn the lifting eye (4A) to ratate with the other hand. If the pressure plate (3A) is not firmly retained, the whole structure of the pipe plug will be carried by the lifting eye (4A) to rotate altogether, and the rubber band (2A) will not be squeezed to expand. In case a pipe is fully filled with various cables, it will be very difficult to seal the orifice of such a pipe with a conventional pipe plug by means of the operation through both two hands. If a pipe is embedded under the ground, one must prostrate oneself so as to position a conventional pipe plug in the orifice of such a pipe. In this case, it is inconvenient to squeeze the rubber band of the installed pipe plug with both hands.